41. As a _____ actor， he can perform， sing， dance and play several kinds of musical instruments.

　　A. flexible

　　B. versatile

　　C. sophisticated

　　D. productive

　　正确答案是

　　42. As a salesman， he works on a （an） _____ basis， taking 10% of everything he sells.

　　A. income

　　B. commission

　　C. salary

　　D. pension

　　正确答案是

　　43. As an excellent shooter， Peter practiced aiming at both _____ targets and moving targets.

　　A. stationary

　　B. standing

　　C. stable

　　D. still

　　正确答案是

　　44. As teachers we should concern ourselves with what is said， not what we think _____.

　　A. ought to be said

　　B. must say

　　C. have to be said

　　D. need to say

　　正确答案是

　　45. As the plane was getting ready to take off， we all _____ our seat belt.

　　A. tied

　　B. locked

　　C. fastened

　　D. closed

　　正确答案是

　　46. At first， the speaker was referring to the problem of pollution in the country， but halfway in her speech， she suddenly _____ to another subject.

　　A. committed

　　B. switched

　　C. favored

　　D. transmitted

　　正确答案是

　　47. At no time _____ other countries.

　　A. China will invade

　　B. will invade China

　　C. will China invade

　　D. invade will China

　　正确答案是

　　48. Be here on Friday _____ the latest.

　　A. at

　　B. by

　　C. for

　　D. in

　　正确答案是

　　49. Because the whole country is in a financial dilemma， the government calls on us to _____ economy.

　　A. make

　　B. practice

　　C. carry

　　D. develop

　　正确答案是

　　50. Before he started the work， I asked the builder to give me an _____ of the cost of repairing the roof.

　　A. assessment

　　B. estimate

　　C. announcement

　　D. evaluation

　　正确答案是